Hydraulic power unit



May 29, 1962 R. L. I OUP 3,036,433

HYDRAULIC POWER UNIT Filed Aug. 3l, 1959 5 Sheets-Sheet 1 May 29, 1962 R. LOUP 3,036,433

HYDRAULIC POWER UNIT Filed Aug'. 5l. 1959 5 Sheets-Sheet 2 j v 754 li L H 6/ 3mm E@ if; ifa /54 6 E Q :5f/ O i i O y i I INVENTOR. a l a l a a iowa/ azz/9,

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May 29, 1962 R. LOUP HYDRAULIC POWER UNIT 5 Sheets-Sheet 3 Filed Aug. 3l. 1959 ifi May 29, 1962 R. L. I oUP HYDRAULIC POWER UNIT Filed Aug. 3l. 1959 5 Sheets-Sheet 4 Q f4 M4@ (5 v/ if;

INVENTOR. FOWJ L V l i May 29, 1962 R. LOUP HYDRAULIC POWER UNIT 5 Sheets-Sheet 5 Filed Aug. 3l, 1959 ...LL-C.

INVENTUR. FWJZJ A az/ff I United States Patent O 3,936,433 HYDRAULIC PGWER UNIT Ronald L. Loup, Manchester, Mich., assignor to Double A Products Company, Manchester, Mich., a corporation of Michigan Filed Aug. 31, 1959, Ser. No. 837,079 9 Claims. (Cl. 60-52) This invention relates to hydraulic power units and particularly to a small compact hydraulic power unit that can have a plurality of directional valves mounted directlyithereon in a manner to eliminate the need for eX- ternal piping connections to the valves.

It is one object of the present invention to provide a small compact hydraulic power unit having one or more directional valves mounted directly thereon without any external piping connections and wherein each valve is in a series pressure supply connection which establishes a priority system of operation so that the supply of pressurized fluid is blocked to all valves farther down the circuit when any valve in the series is shifted.

It is another object of the invention to provide a hydraulic power unit having directional valves mounted thereon in the above described manner wherein additional valves may Ibe added directly to the power unit by the user without disturbing the piping connections to the hydraulic device being controlled by each valve.

It is a further object of the invention to provide a hydraulic power unit having directional valves mounted directly thereon in the above described manner and having a built-in relief valve that provides a safety factor in operating positions of the spools of the directional valves.

It is a still further object of the invention to provide a hydraulic power unit having directional valves mounted directly thereon as described above wherein overheating is avoided by free bypass porting through the valve spools in their neutral positions.

It is a still further object of the invention to provide a hydraulic power unit having directional valves mounted directly thereon as described above wherein the tank return line of each valve is internally ported directly to the reservoir of the unit without passing through any other valve to minimize back pressure.

It is a still further object of the invention to provide a hydraulic power unit having directional valves mounted directly thereon as described above which is factory assembled to assure proper iield operation and provide for lower overall cost as compared to prior art hydraulic units requiring customized mounting and piping of the valves either at the factory or by the purchaser in the field.

It is a still further object of the invention t provide a hydraulic power unit of the type described above having a heat exchanger cast in the reservoir body thereof to permit connection directly to a water source when it is necessary to cool the hydraulic fluid.

It is a still further object of the invention to provide a compact, completely assembled hydraulic power unit having directional valves mounted directly thereon as described above to provide a complete assembly ready to connect directly to hydraulic cylinder lines of a users equipment.

It is a still further object of the invention t0 provide a hydraulic power unit of the type described which is economical to manufacture, easy to operate and disassemble, versatile, and trouble-free operation.

Other objects and features of novelty of the invention will be specifically pointed out or otherwise become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawings wherein:

FIG. l is a perspective view of a hydraulic power unit embodying features of the present invention connected to ice a hydraulic press, the hydraulic power unit being greatly enlarged relative to the size of the press for purposes of clarity;

FIG. 2 is a perspective view of the hydraulic power unit of FIG. 1 connected to a hydraulic jack, the hydraulic power unit being enlarged relative to the hydraulic jack and the truck on which the jack is being used as in FIG. l for purposes of clarity;

FIG. 3 is a perspective view of a hydraulic power unit embodying features of the present invention having four directional valves mounted thereon for operating four separate double-acting hydraulic cylinders;

FIG. 4 is a schematic circuit diagram of a hydraulic power unit embodying features of the present invention having two directional valves mounted directly thereon;

FIG. 5 is an elevational view, partially broken away, of a hydraulic power unit embodying features of the present invention having one directional Valve mounted directly thereon;

FIG. 6 is a View similar to that of FIG. 5 illustrating a hydraulic power unit having four directional valves mounted directly thereon;

FIG. 7 is a plan view of the hydraulic power unit illustrated in FIG. 6;

FIG. 8 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 8-8 Athereof with a portion of the directional valve shown in section;

FIG. 9 is an enlarged sectional view of the structure il lustrated in FIG. 5, taken along the line 9 9 thereof;

FIG. 10 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 10-10 thereof;

FIG. 11 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 11--11 thereof;

FIG. 12 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 12-12 thereof;

FIG. 13 is an enlarged sectional view of the structure illustrated in FIG. 6, taken along the line 13--13 thereof;

FIG. 14 is an enlarged sectional view of the structure illustrated in FIG. 6, taken along the line 14-14 thereof;

FIG. 15 is an enlarged sectional view of the structure illustrated in FIG. 6, taken along the line 15-15 thereof;

FIG. 16 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 16-16 thereof with the pump shaft and oher elements mounted thereon removed;

FIG. 17 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along the line 17-17 thereof with the pump shaft and other elements mounted thereon removed;

FIG. 18 is an enlarged sectional view of the structure illustrated in FIG. 5, taken along'the line 18-18 thereof; and

FIG. 19 is a fragmentary sectional view of a portion of the manifold block of the hydraulic power unit illustrating the built-in relief valve construction.

Referring to FIG. l, a hydraulic power unit 24 illustrating one embodiment of the present invention is disclosed which comprises a reservoir body 26 having a cover plate 28 enclosing the open upper end thereof and a ported manifold 30 mounted directly on top of the cover plate 28. An electric motor 32 is mounted on top of the manifold block 30 with the output shaft thereof extending through the manifold block to operate a hydraulic pump 142 (FIG. 5) within the reservoir body 26 as will be described in greater detail hereinafter. A directional valve 34 operated by electric solenoids 36 and 38 on either end thereof is mounted directly on one side face of the manifold 30 with suitable internal porting provided therebetween to enable pressurized uid to Ypass from the reservoir, through ythe manifold 30, into' the directional valve 34, through the lines 44 and 46 to and from the press cylinder 4u; back through the manifold 3 and into the reservoir body as will also be described in greater detail hereinafter.

This construction provides one unitary assembly that can be connected directly to a double acting hydraulic cylinder 40 of a hydraulic press 42, for example, by hoses 44 and 46, the hose 44 communicating with one side of the piston of the hydraulic cylinder 40 and the hose 46 communicating with the other side thereof. The other ends of the hoses are connected directly to cylinder ports in the manifold 30 as will be described. The directional valve 34 has no external piping connections and, therefore, can be easily disassembled for repair or replacement. Thus, the user only need concern himself with making the simple hose connections between the manifold 30 of the hydraulic power unit and the hydraulic cylinder 40.

Referring to FIG. 2, the hydraulic power unit 24 is illustrated as connected to a hydraulic jack 48 by the vhose 46 having the left end thereof connected to the manifold 30 as previously described. Since the piston of the hydraulic jack 48 will automatically lower due to the weight of the ramp 52 leading to the truck 54 which it is supporting, a second hose connection to the upper side of the piston is not necessary. The hydraulic power unit 24 is designed to readily compensate for this by merely connecting the cylinder port of the manifold 30 to which the hose 44 is connected to an auxiliary tank port on the Yopposite side of the manifold block as will be described in greater detail hereinafter.

The hydraulic power unit 24 is also designed to have one, two, three of four separate directional valves mounted thereon in a very simple building block fashion that enables individual valves tobe easily added or removed without disturbing any external piping connections from the power unit to the hydraulic device being operated thereby. In FIG. 3 the unit 24 is illustrated with four directional valves 58, 60, 62 and 64 mounted thereon.

When four valves are used, adaptor blocks 66 and 68 are mounted on opposite side faces of the manifold block 30 as will he described in greater detail hereinafter and the directional valves are mounted directly on the side and upper faces of the adaptor blocks as illustrated.

With this construction the hydraulic power unit 24 can operate any one of four separate hydraulic cylinders 70, 72, 74 and 76. The hydraulic cylinder 70 is connected directly to two cylinder ports in the manifold 30 by hoses 78 and 80, the hydraulic cylinder 72 is connected directly to cylinder ports in opposite ends of the adapter Iblockr66 by hoses 82 and 84, the hydraulic cylinder 74 is connected directly to a second pair of cylinder ports in the manifold 30 by hoses 90 and 92, and the hydraulic cylinder 76 is connected directly to cylinder ports in opposite ends of the adaptor block 68 by hoses 86 and 88.

As will -be seen from the following description, the internal porting of the hydraulic power unit 24 and the elements mounted thereon connects each of the valves in a series ksupply connection which establishes a priority system of operation so that the pressurized liuid supply is blocked to all valves farther down the circuit when any .one valve in the series is shifted. In the typical automation arrangement illustrated in FIG. 3, the valve 58 is the rst valve in the series, the valve 60 the second, the Valve 62 the third, and the valve 64 the fourth, and each valve controls the hydraulic cylinders '70, 72, 74 and 76, respectively. .By way of example, each of the four hydraulic cylinders illustrated can control separate devices of an automatic welding machine which are operated in sequence, such as,l for example, a loading and unloading device (hydraulic cylinder 70), a locating device (hydraulic cylinder 72), a toggle or wedge clamping device (hydraulic cylinder 74), and a welding device (hydraulic cylinder 76). To begin the operation, the valveV 58 is shifted by one of the solenoids on either end thereof to actuate the hydraulic cylinder 70 to load the workpiece and, thereafter, return to its neutral position. The valve 60 is then shifted to operate the hydraulic cylinder '72 to locate the workpiece, the valve 62 shifted to actuate the hydraulic cylinder 74 vto operate the clamping device, and finally the valve 64- shifted to actuate the hydraulic cylinder 76 to operate the welding device, each of the valves being returned to their neutral position before actuating the next valve.

Referring to FIG. 4, a schematic diagram of a hydraulic power unit having two directional valves mounted thereon is illustrated. This would be a unit similar to that of FIG. l with the second directional valve mounted on the opposite side of the manifold 30 from that on which the directional valve 34 is mounted. Such an arrangement is shown in FIG. 5 wherein the valve 34 isv illustrated on the left face of the manifold 30 and a second valve is illustrated in phantom as being mounted on the right face of the manifold 30.

As illustrated schematically in FIG. 4 a motor 94 is coupled to a hydraulic pump 96 which pressurizes a passageway 98. Of course, the pump 96 obtains its supply of fluid from the reservoir 26 of the hydraulic power unit which is indicated schematically by connecting the pump to tank. It is also noted that in each instance wherein a connection to tank is schematically illustrated in FlG. 4, it is to be understood that this is the schematic representation for connection directly back to the reservoir 26 of the hydraulic power unit. A relief valve 100 is connected to the passageway 98 to prevent the fluid pressure from exceeding a predetermined value before the passageway 98 communicates with a three-position directional valve 102. When the valve is in its neutral position, the pressurized fluid passes directly through the valve 102 and through a passageway 103 to the second directional valve 104. When the valve 104 is in its neutral position, as illustrated, the pressurized fluid passes directly therethrough and returns to tank through a passageway 105. Therefore, the pressurization is very low so as to require the expenditure of a minimum amount of power and to generate a minimum amount of heating.

To enable the pressure within the passageway 98 to be gauged a passageway 106 is connected thereto which, in the actual hydraulic power unit, communicates with a gauge port 248 on one of the faces of the manifold 30 as illustrated in FIG. 5 to permit a pressure gauge to be inserted therein. Similarly, a passageway 108 is connected to the passageway 103 to enable the secondary pressure therein to he gauged, the passageway 108 cornmunicating with a gauge port 252 as illustrated in FIG. 5.

A passageway 110V connected to the passageway 98 provides a second pressure input to the valve '102 which is blocked off when the valve is in its neutral position. Similarly, a passageway 112 provides a second pressure input `for lthe valve 104 which is also blocked off when the valve is in its neutral position. Each valve is provided with passageways 114 and 116, respectively, which communicate the valves with tank and which are both blocked oifV in the neutral position. Passageways 118 and 120 connect the valve 102 with one vertical pair of cylinder ports in the manifold 30, and passageways 122 and 124 connect the valve 104 with the second pair of cylinder ports in the manifold, `all of which are blockedot when the valves are in their neutral positions.

When the val-ve 102 is shifted to the right by energizing the solenoid 126, the `flow of pressurized uid through the valve 102 into` the passageway 103 is blocked and the flow of pressurized fluid from the passageway 110 is directed into the cylinder passageway 118. At the same time the cylinder passageway 120 is communicated directly with tank by the passageway 114 so that the hy- Vdraulic deviceto which the passageways 118 and 120 are one or the other of passageways 122 and 124 with tank and that no pressurized iluid could be introduced thereto since the passageway 103 is blocked oif by the valve 102. Similarly, shifting the valve 102 to the left by energizing the electric solenoid 128 would also prevent the pressurized fluid 4from passing from the passageway 98 through the valve and into the passageway 103. However, in this extreme left hand position the passageway 110 is communicated with the passageway 120 and the passageway 118 is communicated directly with tank through the passageway 114. In this position, the hydraulic device controlled by passageways 118 and 120 would be reversed. When both solenoids 126 and 128 are deenergized the valve 102 is returned to its neutral position and again seals off both of the passageways 118 and 120 and permits the pressurized uid to pass therethrough and through the Valve 104 to tank through the passageway S.

When the valve 102 is in its neutral position, the valve 104 can -be shifted to the right by a solenoid 130 to pressurize the cylinder passageway 122 and connect the cylinder passageway .124 with tank, or can be shifted to the left by a solenoid 132 to pressurize the cylinder passageway 124 and communicate the cylinder passageway 122 with tank.

From the foregoing, it is apparent that a number of additional valves can easily be added between the valve 104 and its connection to tank by means of the passageway 105 to control additional cylinder passageways. In all of these arrangements the connecting passageways are formed either in the manifold 30, the reservoir body 26, the various valve bodies or the adaptor blocks 66 and 68 as will be described to provide a compact assembly which does not require any external piping connections other than the hose connections necessary for connecting the hydraulic power unit to the various hydraulic devices which it is to control. As illustrated schematically in FIG. 4, a passageway 134 is also provided which communicates with tank to provide the auxiliary tank connection 250 (FIG. 5) to which the hose 46 of FIG. 2 is connected when the power unit is arranged to control a one-way hydraulic cylinder such as the hydraulic jack 48.

Referring to FIGS. 5 and 8, the construction of the hydraulic power unit 24 having a single directional valve 34 mounted thereon is illustrated in greater detail. When only the directional valve 34 is used, a return plate 140 is mounted on the right face of the manifold 30, and the ow of pressurized fluid passes from a hydraulic pump 142 coupled to the electric motor 32 by a connector 144, through the manifold 30, into the directional valve 34, across the spool thereof, back into and across the manifold, into and out of the return plate 140, back into the manifold and thence back to the reservoir body 26.

Referring to FIGS. 16 and 17 as well as FIG. 5, the port pattern in the cover plate 28 and the bottom face c-f the manifold 30 is illustrated in detail, as well as bolts 146 which extend through the manifold and cover plate for securing them together. It will be observed that the cover plate is provided With a tank port 148, a drain port 150, a pressure port 152, a tank port 154, a tank port 156, a drain port 158, a tank port 160 and a tank port 162. The bottom face of the manifold is also 'provided with corresponding ports which have been designated by identical numbers to identify the ports in the cover plate which communicate with the ports in the manifold. This same system will be used throughout the following description wherever possible. Consequently, when the bottom face of the manifold 30 is bolted against the upper face of the cover plate 28 by the bolts 146, each of the ports having the same numbers will be aligned with one another. It will -also be observed in FIGS. 16 and 17 that the manifold 30 has a central aperture 164 therein and that the cover plate 28 has a central aperture 166. The pump 142 can Ibe bolted directly to the underside of the cover plate 28 by Ibolts i168 with an operating shaft therefore extending upwardly through the central apertures 166 and 164 to the connector 144 (FIG. 5). Bolts 172 are also provided for bolting the cover plate 28 to the reservoir body 26, and apertures 174 and 176 are provided at opposite ends of the cover plate 28. A ller cap 177 (illustrated in FIG. 5) is mounted on the cover plate 28 and ts within a notch 178 in the cover plate 30 to enable the reservoir to be iilled through the `aperture 174, and a breather filter 180 (illustrated in FIG. 6) is mounted on the cover plate 28 above the aperture 176 and tits within a semicircular notch 182 of the manifold 30.

The port patterns of the mating faces of the manifold 30 and the directional valve 34 are illustrated in FIGS. ll and l2. The face 183 of the manifold 30, as illustrated in FIG. l2, has a pressure port 184, tank port 186, a drain port 188, a first cylinder port 190, a second cylinder port 192 and a secondary pressure port 194. Through various internally drilled passageways, the pressure port 184, tank port 186 and drain port 188 communicate with the pressure ports 152, tank ports 148 and drain ports 150 in the bottom face of the manifold 30 and in the cover plate 28 (FIGS. 16 and 17). Tile face 183 of the manifold 30 is also provided with drilled passageways 196 and 198 which are sealed off by plugs disposed iiush with the face 183. The passageway 196 forms part of the internal passageway network for communicating the pressure port 152 with a pressure port on another face of the manifold and the passageway 198 forms part of the internal passageway network for cornmunicating the tank port 154 on the bottom face of the manifold with a bore 280 having a pressure relief valve disposed therein as will be described hereinafter.

As illustrated in FIG. l1, the face 202 of the directional valve 34 which is bolted to the face 183 of the manifold has the following port pattern: A pressure port 184, tank port 186, secondary pressure port 204, drain port 188, cylinder port cylinder port 192 and secondary pressure port 194. As before, each of the ports in the faces 183 and 202 which have been designated by the same number align with one another when the faces 202 and 183 of the directional valve and manifold are bolted together. However, the secondary pressure port 204 will be sealed off by the face 183 of the manifold since there is no port on the face 183 that will align with the secondary pressure port 204.

Referring to FIG. 8, the directional valve 34 is basically a conventional directional valve having a spool 206 slidably sealed within a central bore 208 and spring centered by springs 210 and 212 acting on each end thereof. The spool 206 is shifted to the right (up, as viewed in FIG. -8) by a solenoid 214 and is shifted to the left (down, as viewed in FIG. 8) by a solenoid 216, each of the solenoids having plungers 218l and 220 projecting therefrom and engaging Vthe ends of the spools in a conventional manner. Each of the solenoids is also provided with pins 221 and 222, respectively, which project from the outer ends thereof and are connected to members 224 for engaging their respective pins 218 and 220 to enable the spool 206 to be manually shifted when necessary. v

As illustrated in FIG. 8, the `spool is in its neutral position. The pressure port 184 is communicated through suitable drilled passageways in the valve body with the secondary pressure port 204, and also communicates with the secondary pressure port 194 across the spool 206. The tank port 186- is sealed off by the spool, as is each of the cylinder ports 190 and 192.

The secondary pressure port 194 on the face 183 of the manifold 30, communicates with a secondary pressure port 194 on face 226 of the manifold as illustrated in FIG. l() through suitable drilled passageways 228 and 230 in the manifold. Referring particularly to FIG. 10 the face226 is also provided with a tank port 160, drain port 158 and a tank port 162, all of which communicate with the ports in the bottom face of the manifold having the same number. The face 226 is also provided with a rst cylinder port 228 and a second cylinder port 230, as Well as bolts 232 for bolting the return plate 140 on the manifold 39.

Referring particularly to FIG. 9, the return plate 140 has blind end ports 162, 230, 4228- and 158, each of which, as do many of the other ports on some of the other faces, has grooves 234 thereabout for receiving O-rings, and cach of which overlie the ports on the face 226 on the manifold having the corresponding number of seal off these ports. The return plate 140 also has ports 194 'and 160 which align with the ports having corresponding numbers on the face 226 and which are communicated with one another by a drilled passageway 236 having a plug inserted in the right end thereof. A third port 238 is also provided in alignment with the ports 160 and 194 and in communication with the drilled passageway 236 for a purpose to be described hereinafter, the port 238 being sealed off by the face 226 of the manifold. Consequently, with the return plate 140 in position, all of the ports on the face 226 of the manifold will be sealed off except the ports 160l and 194 and, therefore, the pressurized fluid passing into the lsecondary pressure port 194 of the return plate will lbe returned to the manifold through the drilled passageway 236, and the tank port 160.

To summarize, the path of flow of pressurized fluid in the single valve arrangement illustrated in FIGS. and 8 is from the pump 142 through the pressure ports 152 in the cover plate 28 and the bottom of the manifold 30 (FIGS. 16 and 17), out of the pressure port 184 in the face 183 FIGS. 8 and l2 of the manifold, into the pressure port 184 in the face 202 (FIG. ll) of the directional valve 34, across the spool 206 (FIG. 8), through the secondary pressure port 194, into the secondary pressure port 194 on the face 183, across the manifold through drilled passageways 228 and 230 and the secondary pressure port 194 on the face 226, into the secondary pressureport 194 and drilled passageway 236 of the return plate 140 and out the tank port V160 thereof (FIG. 9), into the tank port 160 on the face 226 of the manifold (FIG. 10), and finally through the tank ports 160 in the bottom face of the manifold and the cover plate 28 into the reservoir body 26. In this manner, a'continuous flow of pressurized fluid passes from the pump in the reservoir through the manifold, through the directional valve 34, back across the manifold, through the return plate 140, back into the manifold, and thence to the reservoir.

When the spool 206 is shifted to the right (up, as

Vviewed in FIG. 8) by the solenoid 214, Ithe secondary pressure port 194 and the pressure port 184 are sealed olf by the spool, the cylinder port 190 communicates with the tank port 186, and the secondary pressure port 204 communicates With the cylinder port 192. It is again noted that the secondary pressure port 204 is communicated directly with the pressure port 184 by means of suit able drilled passageways (not shown) in the valve body so that it will be pressurized even though the spool prevents communication of the port 184 with either the cylinder port 190 or the secondary pressure port 194. Suitable drilled passageways a-re also formed in the manifold e 30 for communicating the cylinder ports 190 and 192 in the face 183 thereof (FIG. 12) with similar cylinder ports 190 and 192 in a face 244 on the right side of the manifold as viewed in FIG. 8. These latter ports are more clearly illustrated in FIG. 6 wherein a front view of the face 244 is illustrated. Of course, these latter cylinder ports 190 and 192 would be connected directly to a Work device, such as la hydraulic cylinder, by suitable hoses in the manner illustrated in FIG. 1. Thus, with the spool 206 shifted to the right, the cylinder 192 would be pressurized and the cylinder 190 connected with tank so as to shift the hydraulic cylinder in one direction.

Conversely, when the spool 206 is shifted to the left (down, as viewed in FIG. 8) in response to the energization of the solenoid 216, the cylinder port 192 is communicated with tank and the cylinder port 190 is con1- municated with the pressure port 184, the secondary pressure ports 194 and 204 both being sealed off by the spool 206. When both solenoids are deenergized, the spool returns to its neutral position and both cylinder ports 190 and 192 'are again sealed off by the spool and the pressurized huid flow through the pressure port 184, across the spool and out of the valve through the secondary pressure port 194 as previously described.

If it is desired to add a second directional valve to the `hydraulic power unit, the return plate 140 is merely removed and another valve, identical to the valve 134, is bolted to the face 226 of the manifold as indicated in phantom in FIG. 5. rIhe second valve would have the same port pattern las the directional valve 34 as illustrated in FIG. l1, and when bolted to the face 226, the port 194 of the second valve would be aligned with the tank port 162 on the face 226, the port 192 with the cylinder port 230, the port 186 with the tank port 160, the port 204 with the secondary pressure port 194, the port 188 with the drain port 158, and the port 190 with the cylinder port 228. The remaining port 184 in the added 'valve would be sealed off by the face 226 of the manifold.

When in its neutral position the added valve would enable fluid from the secondary pressure port 194 on the face 226 to pass directly across the spool and out of the valve into the tank port 160 on the face 226, and thence to the reservoir body 26 1as previously described. When the spool of the second valve is shifted in one direction it Wil-l communicate one of the secondary pressure ports with the cylinder port 228 and the cylinder port 230 with the tank port 160, and when shifted in the opposite direction will connect the cylinder port 228 with the tank port 160 yand the cylinder port 230 with the other secondary pressure port. Of course, both cylinder ports 228 and Y 230 on the face 226 of the manifold are connected with corresponding cylinder ports 228 'and 230 on the face 244 (FIG. 6) of the manifold by suitable drilled passageways to enable two additional hydraulic hose connections to be made thereto for operating a second hydraulic cylinder.

Referring to FIG. 5, face 246 of the manifold 30 is provided with the ports 248 and 252 which are adapted to have'pressure gauges connected thereto to provide pressure indications `as previously described with reference to FIG. 4. The port 248 communicates with the primary pressure port 152 in the bottom face of the manifold 30 to provide a means for obtaining an indication of the primary pressure developed by the pump 142, and the port 252 communicates with the drilled passage 228 (FIG. 8)

to provide means for obtaining an indication of the secondary pressure. The port 250 is an auxilliary tank port which communicates with the aligned tank .ports 156 in the bottom face of the manifold and in the cover plate 28. The auxiliary tank port 250 is provided for applications such as that illustrated in FIG. 2 wherein a single acting hydraulic jack 48 is Vemployed and one of the hoses coming from one of the cylinder ports is connected directly to the auxiliary tank port.

As previously mentioned, the manifold 30 is also provided with the built-in pressure relief valve 254 as illustrated in FIG. 5'which extends Within the bore 200 extending through the manifold as more clearly illustrated in FIG. 19. A drilled passageway 258 communicates the lower endof the bore 200 with the pressure port 184 as illustrated in dotted lines in FIG. l2. Another passageway 198 is `drilled in the manifold to communicate the 1 bore 20G with the tank port 154 opening on the bottom face of the manifold and aligned with the tank port 154 in the cover plate 128.

A shouldered piston 262 is slidably disposed in a portion 256 of the bore 20G to seal the tank passageway 198 and a suitable spring 264 resiliently engages the shouldered end of the piston to normally maintain it in the position illustrated. A nut and cap lassembly 266 is screwed in the upper end of the .bore 200 and engages the upper end of the spring 264 in a manner to vary the compression thereof to preset the fluid pressure that must act on the lower end of the piston to move it upwardly until it exposes a portion of the tank passageway 198. The pressurized fluid is introduced below the lower end of the piston so as to act thereon through the drilled passageway 258 as previously described. A small passageway 268 is .also provided to communicate the space adjacent the .upper end of the piston 262 with the tank passageway 198 to drain any uid that may work its way into this area.

As will also be observed in FIG. 5, a heat exchanger having a plurality of tubular convolutions 274 is cast directly in the wall of the reservoir body 226 with an inlet 276 and an outlet 278 provided at the upper and lower ends thereof. This permits a water souroe to be directly connected to the inlet and outlet on the reservoir body where it is desired to cool the hydraulic uid. The inlet and outlet connection and the manner in which they cooperate with the ends of the tubular convolutions is more clearly illustrated in FIG. 18.

Referring to FIGS. 6 and 7 when it is desired to mount four directional valves on the hydraulic power unit adaptor blocks 280 and 282 are secured directly to the faces 183 and 226, respectively, of the manifold 30. The directional valve 34 which was previously bolted on the face 183 of the manifold is bolted on a face 284 of the adaptor block 280 to control a cylinder port 290y on one end of the adaptor block and a cylinder port 292 on the other end thereof. A second directional valve 286 can then be mounted on a face 288 of the adaptor 280 to control the cylinder ports 190 and 192 as will be described. In a similar manner, a directional valve 294 can be mounted on a face 296 to control the cylinder ports 228 and 330 on the manifold 30 and a fourth directional valve 302 mounted on a face 304 of the adaptor block 282 to control cylinder ports 298 and 300 opening on opposite ends of the adaptor block 282. Suitable layers of gasket material can be disposed between the engaging faces to improve the seal therebetween.

Referring to FIGS. 6 and 14, face 306 of the adaptor 280 which engages the face 183 of the manifold 30 has a plurality of bolts 388 extending therethrough for securing the adaptor to the manifold. The face 306 also has aport pattern which is identical to the port pattern of vthe directional valve 34; namely, a primary pressure port 184, a tank port 186, a. secondary pressure port 204 which is blocked oi by the manifold, a drain port 188, a first cylinder port v190, a second cylinder port 192, and a second pressure port 194. Each of these ports with the exception of the port 204 align with ports having corresponding numbers on the face 183 of the manifold as did the directional valve 34 when it was directly mounted on the face 183.

Referring to FIGS. 13 and 15 as well as FIG. 14, the tank port 186 and drain port 188 extend completely through the adaptor 280 and open on the face 284 thereof in the positions indicated by the numerals 186 and 188 in FIG. l5. The pressure port 184 communicates with a pressure .port .184 on the face 284 by means of suitable drilled lpassageways 310 and312 in FIG. 13

(which are sealed 01T at the face 288 by suitable plugs) and a drilled passageway 314 in the face 284 of FIG. 15 (which is also sealed olf by a suitable plug). The cylinder port 19t) on the face 306 (FIG. 14) communicates with a cylinder port 190 on the face 288 (FIG. 13), the cylinder port 192 Vof the face 306 with a cylinder port 192 of face 288, the-tank port 186 of face 306 with a tank port 186 of face 288, the tank port 188 of face 366 with a tank port 188 of the face 288, and the secondary l pressure port v204 of face 306 with a secondary pressure port 284vof the face 288.

The face 288 is also provided with a secondary pressure port 194 which communicates with a secondary pressure port 194 on the face 284 of FIG. 15, and the face 284 is provided with a iirst cylinder port 290 which communicates with the cylinder port 298 on one end of the adaptor, and a second cylinder port 292, which cornmunicates -with the cylinder port 300 on the opposite end of the adaptor block.

With this construction the pressurized fluid will flow from the pump 142 into the manifold 30 as previously described, into the primary pressure port 184 on the face 386 of the adaptor 280, out through the primary pressure port 184 on face 288 thereof, into the primary pressure port 184 of the directional valve 286, and, assuming the spool is in its neutral position, across the spool, out the secondary pressure port 194 into the secondary pressure port 194 on the face 288 of the adaptor, ont through the secondary pressure port 1914 on the face 284 of the adaptor, into the pressure port 184 of the directional valve 34, across the spool 206 (assuming it is also in its neutral position), out the pressure port 194 of the valve, into the pressure port 184 on the face 284 of the adaptor, completely across the adaptor and out the secondary pressure port 194 on the face 306 of the adaptor, into the secondary pressure port 194 on the face 183 of the manifold 30, and completely through the manifold and out through the secondary pressure port 194 on the face 226 thereof in the same manner that it previously traveled through the manifold to the return plate 140.

Of course, with the adaptor block 282 mounted on the face 226 in place of the return plate 140, the pressurized fluid will flow through the adaptor block 282, into the valve 294 mounted thereon, back into the adaptor, into the valve 302, and back into the adaptor in exactly the same manner as just `described with regard to the .adaptor 290, and finally back into the manifold 38 through the tank port 162 of the face 226y thereof and thence to the reservoir body 26 as also previously described. When the directional valve 286, which is mounted on the face 288 of the adaptor block 280 is shifted, it will seal off communication between the ports 184 and 194 on the face 288, and will connect the cylinder port 19t) ywith the pressure port 184 and the cylinder port 192 with the tank port 186. Conversely, when the spool is shifted in the opposite direction it will connect the cylinder port 192 With the secondary pressure port 284 and the cylinder port with the tank port 186. Of course, the cylinder ports 198 and 192 on the surface 288 of the adaptor 280 communicate with the cylinder ports 198 and 192 on the face 306 of the adaptor which, in turn, communicate with the cylinder ports 190 and 192 on the manifold 3) to control the hydraulic devices connected thereto by the external hoses as previously described.

When the directional valve 286 is in its neutral position, pressurized iiuid will flow therethrough to the directional valve 34 which can then be shifted to seal olf the pressure ports 184 and 194 on the face 284 of the adaptor from one another, communicate the cylinder port 292 with the secondary pressure port and communicate the cylinder port 290 with the tank port 186. When the spool is shifted in the opposite direction, it will communicate the cylinder port 298 with the secondary pressure and the cylinder 292 with the tank port 186. The cylinder ports 298 and 292 on the face 284 of the adaptor 280 communicate with the cylinder port 290 on one end of the adaptor and the cylinder port 292 on the other end thereof, respectively, to enable external hose connections to be made to the adaptor as illustrated in FIG. 2.

Fromgthe foregoing, it will be apparent that the hydraulic power unit 24 can be assembled in any one of the following combinations: The single valve arrangement illustrated in FIGS. l and 5, the four-valve arrangement illustrated in FIG. 6, a two-valve arrangement Awherein the return plate 140 is replaced with a second valve as illustrated in phantom in FIG. 5, a three-valve arrangement wherein one of the adaptor blocks of FIG. 6 is removed and a single directional Valve is connected to the manifold 30 in its place, and ka two-valve arrangement wherein one of the adaptor blocks of FIG. 6 is removed and replaced with the return plate 140. Still further, the hydraulic power unit of FIG. 6 may be initially assembled with the four directional valves thereon and if it becomes necessary subsequently to remove one of the valves, such as the valve 294 for example, this can be readily accomplished by merely bolting the return plate 146 directly to the adaptor block 282 in place of the directional valve 294 without going to the trouble of removing the adaptor plate 282, and without disturbing any external piping connections. The return plate 140 can be bolted to any one of the various -faces of the adaptor blocks 280 and 282, or either of the faces 183 and 226 of the manifold 3d. The additional port 238 (FIG. 9) is provided in the return plate 140 in communication with the drilled passageways 236 to enable the return plate to be bolted to the various faces wherein the pressure port may be disposed on the other side of the central tank port 160.

While it will be apparent that the embodiments of the invention herein disclosed are well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

l; A hydraulic power unit comprising a reservoir body, a manifold mounted on said reservoir body, said manifold having port and passageway means therein communicating with said reservoir body and providing a predetermined port pattern on two separate faces of the manifold, each of said faces having a directional valve mounted directly thereon with the port pattern of each valve corresponding to and aligned with the port pattern of the face upon which it is mounted, said port and passageway means also providing a irst pair of cylinder ports communicating with the port pattern on one of said faces and a second pair of cylinder ports communicaring with the port pattern on the other of said faces, and pumping means for pumping hydraulic fluid from said reservoir body into the port and passageway means Vof said manifold whereby the directional valves are mounted on their respective faces to control the pair of cylinder ports associated therewith by controlling the ow of pressurized fluid between the reservoir body and the port and passageway means.

2. A hydraulic power unit comprising a reservoir body, a manifold mounted on said reservoir body, a directional valve mounted directly on one face of said manifold, said manifold having a port and passageway means therein communicating with said reservoir body and the ports of said directional valve, said port and passageway means also providing a port pattern on another face of said manifold and a pair of cylinder ports in the mani-` fold, return means on said other face for recirculating pressurized fluid passing from one of the ports on said other face back into another one of the ports on the other face, and pumping means for pumping hydraulic fluid from said reservoir body into the port and passageway means of said manifold, which circulates the uid into the directional valve and across the spool thereof when the valve is in its neutral position, back through and across the manifold into said return means, back into the manifold and then into the reservoir body, said directional valve pressurizing one of said cylinder ports and communicating the other Vdirectly with the reservoir body through the manifold when shifted to one position and pressurizing the other of said cylinder ports and body when shifted to the other of its positions.

, communicating said one cylinder port with the reservoir t,

3. The invention as defined in claim 2 wherein said port and passageway means also provides an auxiliary tank connection communicating the exterior of said manifold with said reservoirbody.

4. A hydraulic power unit comprising a reservoir body, a manifold mounted on said body, said manifold having port and passageway means therein communicating with said reservoir body and providing predetermined port patterns on a pair of opposite faces of the manifold, said port and passageway means also providing a first pair of cylinder ports communicating with the port pattern on one 4face thereof and a second pair of cylinder ports communicating with the port pattern on the other face thereof, first and second directional valves respectively mounted directly on each of said faces, each of said valves having a port pattern therein corresponding to and aligned with the port pattern of the face engaged thereby, and pumping means for pumping hydraulic fluid from said reservoir body into the port and passageway means of said manifold, said port and passageway means circulating the pressurized fluid from the reservoir body through the manifold into said first directional valve, across the spool thereof when the Valve is in its neutral position, back into and across the manifold, into the second directional valve and across the spool thereof when it is in its neutral position, back into the manifold and finally into the reservoir body, each of said directional valves blocking the flow of pressurized uid across the spool thereof and back into the manifold when in one or the other of their shifted positions, each of said directional valves controlling the pair of cylinder ports in the manifold communicating with the port pattern of the face of the manifold engaged by the valve so as to pressurize one of the cylinder ports and communicate the other directly with the reservoir body through the manifold when the valve is shifted to one position and when shifted to the other of its positions pressurizing the other of the cylinder ports and communicating the one cylinder port directly with the reservoir body through the manifold.

5. In a hydraulic power unit adapted to have a plurality of directional valves mounted directly thereon for controlling pairs of cylinder ports in the hydraulic power unit, a directional valve adapted to be mounted on the hydraulic power unit to control one of the pairs of cylinder ports thereof, said directional Valve comprising a body having a central bore extending therethrough and a spool slidably sealed within said bore, means for shifting said spool in one direction from said neutral position to a iirst position and in another direction to a second position, a first pressure port in said body communicating with said central bore, a second pressureport in said body having one end thereof communicating with said irst pressure port and the other end thereof communicating with said central bore, first and second cylinder ports in said body communicating with said central bore, a secondary pressure port Vin said body communicating with said central bore, a tank port in said body communicating with said central bore, each of said ports in the valve body with the exception of said second pressure port communicating with one face of said body in a predetermined port pattern, said first and secondary pressure ports communicating with one another across said spool and each of the other ports being sealed off by said spool when the valve is in its neutral position, said irstpressure port communicating with said first cylinder port and said second cylinder port communicating with said tank port across said spool and each of the other ports being sealed off by said spool when the valve is in said first position, and said second cylinder port communicating with said secondary pressure port and said first cylinder por-t communicating with said tank port across said spool and each of the other ports being sealed off by said spool when the valve is in said second position.

6. A hydraulic power unit comprising a reservoir body, a manifold mounted on said reservoir body, an adaptor mounted directly on a first face of said manifold, a first directional valve mounted directly on a first face of said adaptor, a second directional valve mounted directly on a second face of said adaptor, return means mounted directly on a second -face of said manifold, and pumping means for pumping hydraulic iiuid from said reservoir body into said manifold under ressure, said manifold and adaptor having port and passageway means therein for circulating the pressurized uid from the reservoir body through the manifold `and the adaptor, into and out of said first valve across the spool thereof when it is in its neutral position, through the adaptor into and out of said second directional valve across the spool thereof when it is in its neutral position, back through the adaptor and the manifold, into and out of said return means and finally through the manifold into the reservoir body, said port and passageway means including a tirs-t pair of cylinder ports in said manifold controlled by said rst directional valve and a second pair of cylinder ports in said adaptor controlled by said second directional valve.

7. The invention as defined in claim 6 wherein said return means comprises a third directional valve and wherein said port and passageway means of the manifold includes a third pair of cylinder ports in said manifold controlled by said third directional valve, said third valve recirculating the pressurized fluid directly across the spool thereof and back into the manifold when in its neutral position.

8. The invention -as defined in claim 6 wherein said return means comprises a second adaptor mounted on said second face of the manifold, a third directional valve mounted on a rst face of said second adaptor, and a second directional valve mounted on a second face of said second adaptor, the second adaptor having port and passageway means therein for circulating the pressurized fluid coming from the manifold into and through said second adaptor into the said third directional valve, across the spool of the third directional valve when in its neutral position, back into and through the second adaptor to the fourth directional valve and across the spool thereof when in its neutral position back into said second adaptor, and finally through the second adaptor into the manifold after which it is returned to the reservoir body as previously described, said port and passageway means of said second adaptor including a fourth pair of cylinder ports communicating with and controlled by said fourth directional valve, said third pair of cylinder ports in the manifold communicating with and controlled by said fourth directional valve.

9. In a hydraulic power unit adapted to have a plurality of directional valves mounted directly thereon for controlling pairs of cylinder ports in the hydraulic power unit, a manifold mounted on the reservoir body of the power unit, and an adaptor mounted directly on a first face of said manifold, said manifold and adaptor having port and passageway means therein communicating with said reservoir body and providing a predetermined port pattern on said irst face and a second face of the manifold and a third and fourth face of said adaptor, each of said second third and fourth faces being adapted to have a directional valve mounted directly thereon with the port pattern of the valve corresponding to and aligned with the port pattern of the face upon which it is to be mounted, said port and passageway means also providing a first pair of cylinder ports communicating with said irst face of said manifold and a second pair of cylinder ports in said manifold communicating with said second face thereof and a third set of cylinder ports in said adaptor communicating with said third face thereof, said first set of cylinder ports being adapted to be controlled by the directional valve mounted on said fourth face of the adaptor, said second pair of cylinder ports being adapted to be controlled by a directional valve mounted on said second face of the manifold and said third set of cylinder ports being adapted to be controlled by the third valve mounted on said third face of the adaptor.

References Cited in the tile of this patent UNITED STATES PATENTS 2,042,186 Peterson May 26, 1936 2,511,184 Walling June 13, 1950 2,605,613 Grebe Aug. 5, 1952 2,635,586 Kuhn Apr. 21, 1953 2,679,727 McLeod June 1, 1954 2,693,824 Harrington et al. Nov. 9, 1954 2,781,879 Ebersold Feb. 19, 1957 

